British Prime Minister David Cameron said he will offer a "profound apology" if his one-time communications chief and former editor at the now-defunct tabloid News of the World is found to have lied about his role in the phone-hacking scandal.

Cameron, speaking at an emergency parliamentary session, said if Andy Coulson knew about the hacking, he would have lied to him, the police and complaints commission and perjured himself and could expect to face severe criminal charges. Coulson has been arrested in connection with the phone hacking scandal.

"I have an old fashioned view about innocent until proven guilty. But if it turns out I've been lied to, that would be a moment for a profound apology," Cameron told MPs. "And in that event, I can tell you I will not fall short."

Cameron said Coulson's work at Downing Street has never been the subject of a serious complaint but that he takes responsibility for hiring him.

U.K. Prime Minister David Cameron said Andy Coulson should be considered innocent until proven guilty.
((TV via PA/Associated Press))

"People will of course make judgments about it. Of course I regret it and I am extremely sorry about the furor it has caused," Cameron said. With 20/20 hindsight and all that has followed, I would not have offered him the job and I expect that he wouldn't have taken it."

"You live and you learn and believe you me, I have learned," Cameron said.

Lawmaker Louise Mensch told the House of Commons on Wednesday that officials had revoked Lambert's parliamentary pass for breaking strict rules on where journalists can film.

A "Save Gobby" campaign erupted on Twitter, with lawmakers and journalists offering support.

The BBC said it was "looking into this matter with the House authorities."

(The Associated Press)

Miliband said Cameron was warned about Coulson but that he chose to ignore those warnings.

Cameron is being grilled during an all-day debate in Parliament. The emergency question session, which has delayed the start of Parliament's summer recess, follows the dramatic testimony by News Corp. Rupert Murdoch earlier Tuesday at an emergency House of Commons committee hearing.

News of the World is accused of hacking into the phones of celebrities, politicians, other journalists and even murder victims. The long-simmering scandal gained heightened interest with the revelation that journalists accessed the phone of Milly Dowler in search of scoops while police were looking for the missing 13-year-old.

Cameron admitted, however, that both the ruling Conservatives and the opposition Labour parties had failed to pursue key developments in the hacking case over the years.

"The greatest responsibility I have is to clear up this mess," he said.

Cameron told lawmakers a government inquiry would investigate whether other media organizations besides News of the World also committed illegal acts over the years.

Cameron also denied any of his staff met with police in an attempt to pressure them to drop the investigation.

"To risk any perception that No. 10 (Downing Street) was seeking to influence a sensitive police investigation in any way would have been completely wrong," he said.

MPs also questioned Cameron about his meetings with News Corp. executives more than two dozen times from May 2010 to this month — meetings that were criticized by Miliband.

Meanwhile, a House of Commons committee on Wednesday blasted both News International — the News Corp. unit which operates the British papers — and London Metropolitan Police for their performance throughout the scandal.

"We deplore the response of News International to the original investigation into hacking. It is almost impossible to escape the conclusion ... that they were deliberately trying to thwart a criminal investigation," said the Home Affairs committee.

On Tuesday, Murdoch denied any responsibility for the scandal that has embroiled his media empire, telling British MPs he was "betrayed" by some of his staff and was unaware of the practices at the News of the World.

Murdoch, appearing at the hearing with his son James, also a News Corp. executive, reiterated his apology for the actions of some employees at the tabloid, saying the eavesdropping plots left him "ashamed" and "humbled."

But the 80-year-old Australian-born media mogul testified he hasn't considered stepping down in the wake of the scandal and a revived criminal investigation involving the actions of staff and editors at the paper.

"Because I feel that people I trusted — I’m not saying who, I don’t know what level — have let me down and I think that they behaved disgracefully and betrayed the company and me, and it’s for them to pay," Murdoch told MPs.

"I think that, frankly, I’m the best person to clean this up."

The Murdochs' appearance was followed by former News International executive and News of the World chief editor Rebekah Brooks, who apologized to the committee for the phone intercepts, acknowledged "mistakes" were made under her watch and expressed regret the corporation was "too slow" in responding to revelations about the practices.

Brooks, who resigned last week from her senior position in Murdoch's organization, also told MPs she was aware the News of the World used private detectives.

But she testified the hiring of private investigators was the responsibility of the managing editor, and insisted she only learned in 2006 that a private investigator later convicted of criminal charges in the phone-hacking scandal was working for the paper.

She also denied she knowingly sanctioned payments to police, despite her previous testimony to U.K. legislators in 2003 that Murdoch's flagship paper had paid police officers for information.

"I can say that I have never paid a policeman myself, I have never sanctioned or knowingly sanctioned a payment to a police officer," she said. "I was referring [in 2003] to the wide-held belief, not widespread practice, and in fact, in my experience of dealing with police, the information they give to newspapers comes free of charge."

Brooks was arrested Sunday and freed on bail in connection with the phone-hacking investigation, which has raised questions about Murdoch's empire's connections to and influence over Britishpoliticians and police.

Brooks maintained in her testimony on Tuesday that she did not know any phone hacking was going on when she was editor between 2000 and 2003, and called the hacking of Dowler's phone "abhorrent."

Protester aims pie at Murdoch

Tuesday's committee hearing was briefly suspended following a protester's attempt to hit the media mogul with what appeared to be a plate of shaving foam.

Murdoch was responding to a final set of questions when the protester, who had been sitting in the audience, lunged toward Murdoch. The protester was then struck by Murdoch's wife, Wendi Deng, who jumped up to defend her husband.

Murdoch was not injured in the incident.

The scandal has already destroyed News of the World, cost the jobs of Brooks and Wall Street Journal publisher Les Hinton, and ended the elder Murdoch's dream of taking full control of a lucrative satellite broadcaster, British Sky Broadcasting.

Murdoch is eager to stop the crisis from spreading to the United States, where many of his most lucrative assets — including the Fox TV network, 20th Century Fox film studio, the Wall Street Journal and the New York Post — are based.

Police have already arrested 10 people, including other former News of the World reporters and editors, in the wake of the phone-hacking scandal.